Title 24, Part 6, HERS design review, energy efficiency


Complying with Title 24 can be tough.

Energy efficiency adds costs to the project, and the Efficiency Standards are becoming increasingly complicated with each code cycle. Home Energy Rating System (HERS) measures are a series of field verifications and diagnostic tests that validate energy efficiency under California State Energy Code – Title 24 Part 6. Many HERS measures are mandatory, and all are required to be cataloged in an online registry. During construction, a missed HERS measure can lead to delays in Certificates of Occupancy and/or costly change orders. Projects are most vulnerable if systems are not properly designed or if testing parameters are not discussed early.

The HERS process aims to confirm the energy efficiency of building systems within residential and some non-residential buildings. Whether you’re building a multifamily complex or a new leasing center, HERS testing may be necessary to validate system efficiencies. In order to mitigate the potential headache of matching or exceeding these standards, there are several methods you can employ to ensure that your building’s HERS certification process is as smooth as possible, including:

1.HERS Design Review
One of the things building inspectors look for within HERS documentation is proof of proper fan efficacy for your installed HVAC systems. Fan efficacy is the measurement of the fan airflow in relation to the size of the HVAC system. It also considers how effective the fan is in relation to the power used. To ensure that your installed systems don’t fail their mandatory fan efficacy test, a HERS design review can be performed early on in design, particularly during early construction documents phase. Testing occurs when permanent power is available, so the window for correcting issues before final occupancy is relatively small. By verifying fan efficacy before any future problems arise, you will minimize the chance of the fans failing during final HERS testing and possibly needing to rip out drywall and replace your systems.

2.ACCA Manual J, D & S
Fan efficacy is often affected by the way ducts are designed throughout the building. If the ductwork throughout the building is inefficient or improperly sized, you not only run the risk of failing your airflow test, but you may also see unnecessary electricity costs as the installed systems will have to work harder and longer before reaching their designed heating and cooling targets (or possibly never reaching them). ACCA Manual J, D & S is a design phase measure that visually and mathematically calculates the duct design before construction even begins so the mechanical installer for your building will have little to no issue with duct sizing and installation. Not only will this reduce labor costs during construction, but it will also reduce energy costs in the long run.

3.Quality Insulation Installation (QII)
QII is an optional HERS measure for buildings which seek to lower energy costs and increase comfort levels by thickening the building envelope through air-tight, blanketed insulation. Insulation is not always installed perfectly. Gaps can be created when it is not properly fitted around electrical boxes. Electrical wires running across joist bays can compress insulation. Because of this, the algorithms in the compliance software can de-rate value of the insulation being installed. With proof of proper insulation techniques provided by QII, you are given full credit in your energy model for the insulation being installed. With proper training for the construction team and a thorough inspection afterwards, your building envelope can be sealed so securely that other HERS measures are more likely to pass their minimum thresholds. What’s more, well insulated buildings require less heating and cooling, thus saving the end user money and reducing wear and tear on the owner’s equipment.

HERS testing is a valuable and sometimes necessary set of standards to not only reduce energy costs but ensure that indoor air quality for all occupants is optimal and comfortable as well. Every building owner can benefit from HERS testing, and providing early due diligence on design based on testing protocols can improve successful testing and deliver the value of your building.

Contributing Writer: Burke Boydell